dt-bindings: serial: Convert STM32 UART to json-schema

Convert STM32 UART bindings to json-schema.
Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Signed-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/serial/st,stm32-uart.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/serial/st,stm32-uart.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+maintainers:
+  - Erwan Le Ray <erwan.leray@st.com>
+
+title: STMicroelectronics STM32 USART bindings
+
+allOf:
+  - $ref: rs485.yaml
+
+properties:
+  compatible:
+    enum:
+      - st,stm32-uart
+      - st,stm32f7-uart
+      - st,stm32h7-uart
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  clocks:
+    maxItems: 1
+
+  resets:
+    maxItems: 1
+
+  label:
+    description: label associated with this uart
+
+  st,hw-flow-ctrl:
+    description: enable hardware flow control
+    $ref: /schemas/types.yaml#/definitions/flag
+
+  dmas:
+    minItems: 1
+    maxItems: 2
+
+  dma-names:
+    items:
+      enum: [ rx, tx ]
+    minItems: 1
+    maxItems: 2
+
+  wakeup-source: true
+
+  rs485-rts-delay: true
+  rs485-rts-active-low: true
+  linux,rs485-enabled-at-boot-time: true
+  rs485-rx-during-tx: true
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - clocks
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/clock/stm32mp1-clks.h>
+    usart1: serial@40011000 {
+      compatible = "st,stm32-uart";
+      reg = <0x40011000 0x400>;
+      interrupts = <37>;
+      clocks = <&rcc 0 164>;
+      dmas = <&dma2 2 4 0x414 0x0>,
+             <&dma2 7 4 0x414 0x0>;
+      dma-names = "rx", "tx";
+      rs485-rts-active-low;
+    };
+
+...

Documentation/devicetree/bindings/serial/st,stm32-usart.txt

-* STMicroelectronics STM32 USART
-
-Required properties:
-- compatible: can be either:
-  - "st,stm32-uart",
-  - "st,stm32f7-uart",
-  - "st,stm32h7-uart".
-  depending is compatible with stm32(f4), stm32f7 or stm32h7.
-- reg: The address and length of the peripheral registers space
-- interrupts:
-  - The interrupt line for the USART instance,
-  - An optional wake-up interrupt.
-- clocks: The input clock of the USART instance
-
-Optional properties:
-- resets: Must contain the phandle to the reset controller.
-- pinctrl: The reference on the pins configuration
-- st,hw-flow-ctrl: bool flag to enable hardware flow control.
-- rs485-rts-delay, rs485-rx-during-tx, rs485-rts-active-low,
-  linux,rs485-enabled-at-boot-time: see rs485.txt.
-- dmas: phandle(s) to DMA controller node(s). Refer to stm32-dma.txt
-- dma-names: "rx" and/or "tx"
-- wakeup-source: bool flag to indicate this device has wakeup capabilities
-- interrupt-names, if optional wake-up interrupt is used, should be:
-  - "event": the name for the interrupt line of the USART instance
-  - "wakeup" the name for the optional wake-up interrupt
-
-
-Examples:
-usart4: serial@40004c00 {
-	compatible = "st,stm32-uart";
-	reg = <0x40004c00 0x400>;
-	interrupts = <52>;
-	clocks = <&clk_pclk1>;
-	pinctrl-names = "default";
-	pinctrl-0 = <&pinctrl_usart4>;
-};
-
-usart2: serial@40004400 {
-	compatible = "st,stm32-uart";
-	reg = <0x40004400 0x400>;
-	interrupts = <38>;
-	clocks = <&clk_pclk1>;
-	st,hw-flow-ctrl;
-	pinctrl-names = "default";
-	pinctrl-0 = <&pinctrl_usart2 &pinctrl_usart2_rtscts>;
-};
-
-usart1: serial@40011000 {
-	compatible = "st,stm32-uart";
-	reg = <0x40011000 0x400>;
-	interrupts = <37>;
-	clocks = <&rcc 0 164>;
-	dmas = <&dma2 2 4 0x414 0x0>,
-	       <&dma2 7 4 0x414 0x0>;
-	dma-names = "rx", "tx";
-};